Come Monday, while you’re trimming the tree and yelling at the kids, Diane Sawyer will alight to one of the most talked- about, agonized over, and carefully watched thrones in network television. The cool, blond, veteran news babe will become solo anchor of ABC’s “World News.”

Her day in an iconic job that reeks of prestige, a post that has chewed up and spit out many a news reader, has been a long time coming. There are just three human beings so anointed on earth, each of whom sets the pace for the rest of the night’s TV watching. Each with a budget in hair spray alone that could feed a small village.

And, for the first time in history, two anchor chairs are to be filled by people who have the option of wearing skirts to work, a cultural sea change nothing short of groundbreaking.

So why is ABC acting as if it’s in denial?

And why is the network behaving as if it’s preparing for Diane’s doom?

ABC, the perpetual also-ran after NBC News, helmed by marquee god Brian Williams, has shoved the TV survivor (she turns 64 the day after her debut) into the coveted slot without fanfare, prohibiting even a single pre-show interview. Plus she begins her duties in the dead TV week that ends with Christmas.

The brass seem to believe that if everyone simply acts as if nothing interesting is happening, no one will notice that the world has changed.

But it has. And I have a prediction: The experiment will fail.

To say that elevating Sawyer is anything other than affirmative action is a fantasy that the network must face. Yes, the long-ago aide to President Nixon is a WASP with a long on-air career. But she is a dame. And one who has toiled in the perky realm of morning TV, a lead-in that will not sit well with older viewers who make up the bulk of news watchers, folks accustomed to gravelly voices and the illusion of gravitas.

ABC is counting on one thing: She’s not Katie Couric.

Well, who is she?

Sawyer’s recent flubs and missteps are legendary. The only interviewer to land a chat with Tom Cruise’s wife, Katie Holmes, Sawyer babbled for eight minutes about the blank-eyed mom’s hair and shoes before red-faced producers abruptly halted the segment. She never asked about a book claiming that Holmes’ daughter, Suri, was created from the frozen sperm of Scientology founder L. Ron Hubbard. Was she afraid ?

During coverage of President Obama’s inauguration, Sawyer caused many viewers to lunge for the YouTube to see her slur her words bizarrely, show off her legs, and prattle about the Jonas Brothers to horrified co-host Robin Roberts.

ABC is mucking up a formula that has kept it firmly in the No. 2 spot. It replaced Sawyer with the “serious” George Stephanopoulos on “Good Morning America,” putting the elfin news babe on the air at a time of day when people would rather focus on trifles and Tiger Woods, not foreign policy and global warming.

I see Sawyer duking it out with Couric for third place.

Not a pleasant place.

Riders are $ore over MT-Ache

Life in New York is about to go from cruel to unbearable — to a bit hilarious. First, the cruel.

The fat cats who run your subways and buses into the ground are promising, from behind blacked-out windows of Town Cars, to slash train service, eliminate bus and subway lines, cut student freebies and reduce runs on nights and weekends to the point of nonexistence.

Now, the unbearable. Unionized workers of the Metropolitan Transportation Authority will receive generous — I say monstrous — 11.3 percent raises over three years. You read that right. At a time when Gov. Paterson has yanked millions from the budget and tax revenues aren’t cutting it, employees enjoy Bernie Madoff-style increases in salary.

Of course, to ensure that thousands of transit employees get paid, the MTA has to lay off 700 of their colleagues. Enjoy your raise, Mr. Conductor.

And the hilarious.

The Rev. Al’s daughter Dominique Sharpton — who faces charges she cursed a cop and resisted arrest after erratically driving her car — is leading the charge against cutting student MetroCards. She says slashing cards will lead to higher dropout rates, violence and arrests. Will it also lead to road-rage incidents, I wonder?

The MTA claims it hasn’t cut service. Yet. But trying to squeeze onto a train already feels like a contact sport. Dip into stimulus funds. Greedy unionists can take a lower raise.

Somebody, please. Give us a break.

Saving face-lifts

A clutch of body-insecure people turned out in Times Square, in the rain, to protest not for socialized health care, but against a proposed 5 percent federal tax on all-important Botox shots, tummy tucks and rhinoplasty. It’s called the “Botax.” Now there’s something we can all rally around.

But this was no grass-roots demonstration by ladies who believe a face-lift is a civil right. The protest was organized by Park Avenue plastic surgeon Dr. Stephen Greenberg, who got his clients to stand in inclement weather last weekend. These folks aren’t even rich, the doc insisted.

“They’re saving every penny to look better and feel better,” he said.

And the doc is scooping it up. Every last, dirty penny.

Acting pound-foolish

Stop it before we all get sick!

First the city produced TV ads that showed in grotesque detail the horrors smoking can do to your face and body. We know, Mayor Mike. We know.

Not content to ruin our appetite, the city set out to make us skip dinner entirely. The Health Department introduced a gross-out video on its own Web site and on YouTube that features a man downing a glass that appears to contain globs of fat. It’s supposed to put you off of sugary sodas. Of course, fruit juice probably packs on as many pounds as soda, but picking on the healthy-seeming beverage is not nice.

The city has banned indoor smoking, which represents a step forward for clean air. So why turn around and gunk up the airwaves with this new, vile form of pollution?

We live in one of the slimmest cities in the country. Will the nanny police be happy once we’re all anorexic?

Ground Chuck!

It’s ugly when senators attack.

In a shocking display of diva-like behavior, Chuck Schumer called a hardworking US Airways flight attendant a “bitch” after she asked the pol to shut off his cellphone so the shuttle flight might take off. First, Schumer argued like a, well, bitch. Then he leaned over to Sen. Kirsten Gillibrand and leveled the “B” bomb.

He should not be permitted to fly on the taxpayer dime. A groveling apology is in order from this jerk.